可能用到的API声明:[DllImport("user32.dll", EntryPoint="SendMessage")] private static extern int SendMessage (IntPtr hwnd, int wMsg, int wParam, int lParam);[DllImport("user32.dll")] private static extern int SetForegroundWindow (int hwnd); private const int WM_SYSCOMMAND = 0x112; private const int SC_MAXIMIZE = 0xF030;
[另 转愚翁的 参考一下]http://blog.csdn.net/Knight94/archive/2006/03/16/625809.aspx我介绍两个主流的方法。方法一:使用Mutex来进行1. 首先要添加如下的namespace:using System.Threading; 2. 修改系统Main函数,大致如下: bool bCreatedNew; //Create a new mutex using specific mutex name Mutex m =new Mutex( false, "myUniqueName", out bCreatedNew ); if( bCreatedNew ) Application.Run(new yourFormName()); 如上面编码就可以了,要注意的一点是,在给Mutex起名字的时候,不要太简单,以防止和其他程序的Mutex重复,从而达不到所预想的效果。 方法二:使用Process来进行1. 首先要添加如下的namespace:using System.Diagnostics;using System.Reflection; 2. 添加如下函数: public static Process RunningInstance() { Process current = Process.GetCurrentProcess(); Process[] processes = Process.GetProcessesByName(current.ProcessName); //Loop through the running processes in with the same name foreach (Process process in processes) { //Ignore the current process if (process.Id != current.Id) { //Make sure that the process is running from the exe file. if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName) { //Return the other process instance. return process; } } } //No other instance was found, return null. return null; } 3. 修改系统Main函数,大致如下: if( RunningInstance() == null ) Application.Run(new yourFormName()); 如上面编码就可以了,要注意的一点是,在判断进程模块文件名是否相等这部分的代码,是可选的。如果当前的程序在文件系统中只存在一个的话,以上的方法是可以的;否则不要删除这部分的代码。 对比两种方法,就效率和简便性来说,前一种方法是最好的,也是我比较喜欢的;后一种方法,速度比较慢,其次通过ProcessName去系统中查寻,有可能查出来的Process并不是我想要得,虽说在后面加了文件目录判断,但是其含有潜在的问题(前面已经说出来)。不过,第一种方法也有缺陷,就是扩展性操作不方便,例如:让程序只运行一次,如果程序已经运行,把它弹出并显示到最前面。对于此,后一种方法就很有优势了。
{
bool ret;
Mutex mutex = new Mutex(true, Application.ProductName, out ret);
if(ret)
{
Application.Run(new Form1());
mutex.ReleaseMutex();
}
else
{
// 查找该程序的进程
Process[] processArray = Process.GetProcessesByName(Application.ProductName);if(processArray.Length >0)
{Process curProcess = Process.GetCurrentProcess();//查找已运行的进程
foreach(Process p in processArray)
{
if(p.Handle != curProcess.Handle)
{
//得到句柄
IntPtr hWnd = processArray[0].MainWindowHandle;//最大化
SendMessage(hWnd,WM_SYSCOMMAND,SC_MAXIMIZE,0);//或者只是前台显示
//SetForegroundWindow(hWnd);
return;
}
}
}
}
}
private static extern int SendMessage (IntPtr hwnd, int wMsg, int wParam, int lParam);[DllImport("user32.dll")]
private static extern int SetForegroundWindow (int hwnd);
private const int WM_SYSCOMMAND = 0x112;
private const int SC_MAXIMIZE = 0xF030;